1. Field of the Invention
The present invention relates to an X-ray source in which an X-ray tube and its power supply are integrated with each other.
2. Related Background Art
A nondestructive inspection system for observing the internal structure of a sample as a fluoroscopic image without destroying the sample uses an X-ray generator incorporating therein an X-ray tube for irradiating the sample with an X-ray, an X-ray imaging apparatus (XI) detecting the X-ray transmitted through the sample, etc.
As the X-ray source of the X-ray generating apparatus, one in which an X-ray tube and its power supply are integrated with each other has conventionally been known in general (see, for example, Japanese Patent Application Laid-Open No. 2001-135496). As such a kind of integrated X-ray source, the X-ray source A shown in FIG. 1 has conventionally been known in general.
The X-ray source A shown in FIG. 1 comprises a power supply B in which a high-voltage generating part B2, a high-voltage line B3, a socket B4, etc. are molded in an insulating block B1 made of an epoxy resin; and an X-ray tube C incorporated therein such that a bulb part C1 is dipped into a high-voltage insulating oil B6 in a reservoir recess B5 formed in the insulating block B1.
Fixed onto the surface of the insulating block B1 on the side where the reservoir recess B5 opens in the power supply B is a shield plate B7 securing the X-ray tube C and covering the opening of the reservoir recess B5. A bottom plate B8 is secured to the opposite surface of the insulating block B1. The shield plate B8 is formed with an opening B9 through which the bulb part C1 of the X-ray tube C is inserted, whereas an attachment flange C2 of the X-ray tube C is secured to the surroundings of the opening B9.
The X-ray tube C comprises the bulb part C1 accommodating therein a support member C3 (having a target), an X-ray generating part C5 containing a target C4 at the leading end part of the support member C3 (having the target), and an electron gun part C6 accommodating an electron gun which emits an electron beam to the target C4. The X-ray generating part C5 is arranged concentrically with the bulb part C1 on the opposite side of the attachment flange C2 from the bulb part C1, whereas the axis of the electron gun part C6 is orthogonal to the axis of the X-ray generating part C5 and bulb part C1.
Such an X-ray tube C is constructed so as to receive a high voltage from the high-voltage generating part B2 of the power supply B by way of the high-voltage line B3 when a high-voltage applying part C7 at the base end part of the support member C3 (having the target) projecting from the bulb part C1 fits into the socket B4 molded in the insulating block B1 of the power supply B.
In the conventional X-ray source A shown in FIG. 1, the shield plate B7 and bottom plate B8 are secured to the insulating block B1, which is made of the epoxy resin, with a plurality of securing screws B10. As the structure therefor, a plurality of female-threaded tubes B11 to mate with the respective securing screws B10 are buried in the insulating block B1.
It has been considered problematic that, if the female-threaded tubes B11 buried in the insulating block B1 and the securing screws B10 screwed therein are made of a metal, they become conductive foreign matters and induce discharges when the high-voltage generating part B2 of the power supply B generates a high voltage. It has also been considered problematic that, if the female-threaded tubes B11 and securing screws B10 are made of a resin, they are charged when the high-voltage generating part B2 generates a high voltage, whereby disturbances are induced in electric fields.